Sewage water can be purified for recycling with the action of

Select the correct statement from the following.

In how many stages did the biologists from Humboldt State University perform wastewater treatment?

Identify the correct statement from the following.

Statement $S$: In the primary stage of sewage treatment,physical particle matter is removed from water through filtration and sedimentation.
Reason $R$: Through sedimentation,soil or small pebbles are removed.

What is the correct sequence of processes in a sewage treatment plant?